PSAT Math Multiple-Choice Question 420: Answer and Explanation

Question: 420

In the figure shown above, what is the value of f(3) - g(3)?

• A. -3
• B. 0
• C. 3
• D. 6

Correct Answer: A

Explanation:

A

Difficulty: Medium

Getting to the Answer: Graphically, the notation f (3) means the y-value when x = 3. It may help to draw dots on the graph. Find x = 3 on the x-axis, then mark each function at this x-value on the graph as shown here:

Now, read the y-coordinates from the graph, paying close attention to which function is which, and subtract: f (3) = -2 and g(3) = 1, so f (3) - g(3) = -2 - 1 = -3. (A) is correct.